The American Club Racing (ACR) variant was first introduced as a package on the 1999 Viper GTS (Phase SR II).
The ACR used the same K&N air filter and smooth tubes from the GT2 for the power gains along with the BBS rims. A new 5-point harness with the ACR logo was installed for both the driver and passenger.
For the 1999 model year, Koni adjustable shocks were installed and changed to Dynamics later in the 2000 model year. Lastly, the spring rates were increased. The ACR was available in solid color or with stripes with the color choices changing yearly along with AGR badging.